Prosecutors are considering launching the first case against an undercover police officer deployed to infiltrate political campaigns.

The Crown Prosecution Service is examining allegations of wrongdoing by Jim Boyling, a former member of a covert Metropolitan police unit which planted undercover officers in political groups for four decades.

He has been under investigation following allegations in the Guardian that he concealed a relationship with a political campaigner from his police bosses and had two children with the woman.

Boyling has also been accused of divulging classified police information to her, including the identities of at least two undercover officers.

Prosecutors have not specified the potential offences they are studying, and it is unclear whether their work is related to these allegations.

Boyling, a serving detective constable in the Met, denies that he committed any criminal or misconduct offence while working for the police.

A file on his case is understood to have been passed to the CPS by police investigating the activities of more than 100 spies who infiltrated political groups from 1968. That inquiry, led by Mick Creedon, chief constable of Derbyshire police, is also looking at the possibility of prosecuting dozens of undercover officers who slept with women they were spying on and who stole the identities of dead children.

Police started an internal investigation into Boyling's conduct in January 2011 after the Guardian revealed how he adopted a false identity and pretended to be a cleaner called Jim Sutton while he infiltrated environmental groups between 1995 and 2000.

In 1999, he started a relationship with a political activist and began living with her. The following year, he disappeared from her life, claiming that he had to go abroad to "sort out his head". The woman, identified only as Laura, spent more than a year searching for him, travelling around South Africa for three months, until she found him in a London bookshop in 2001. He told her that he was a police officer who had been sent to live undercover among the activists.

According to Laura, he claimed that he had regretted what he had done and was still in love with her. They then resumed the relationship within weeks and had two children together. Laura says that at the time she was vulnerable and traumatised by the experience, and he fabricated a story to make her forgive his betrayal and entrap her deeper in the relationship.

According to Laura, he repeatedly promised her that he would leave the police and start a new life together while seeking to isolate her from other activists.

She says he concealed their relationship from his managers while he continued to work for Special Branch on other duties. She says that he made her change her name by deed poll to diminish the chances of their relationship being discovered. He rejects this claim, saying that she made the change "at her own instigation".

She also claimed that he only told a senior officer about their relationship when they married under her new name in 2005.

That claim is also rejected by Boyling, who said: "Senior officers were made aware of these circumstances from late 2001/early 2002. When we married in 2005, I made a written declaration to the vetting unit."

Boyling denies her allegation that he disclosed to her the identities of at least two other spies who worked for his unit, the Special Demonstration Squad.

One of them, she says, was Bob Lambert, a key member of the SDS who had a child with an activist while he was undercover in environmental and animal rights groups.

Laura has told how Lambert visited her and Boyling at their home in 2007, a year before they divorced.

Laura says she later identified Lambert and another SDS spy, John Dines, to fellow campaigners. Both have since been unmasked.

Boyling has previously said his ex-wife's account of their relationship is incorrect, although he has declined to elaborate.

Asked about Boyling, the CPS said that in July last year, the police sent them a file and asked whether a "suspect" should be charged. In September, the CPS asked for more information about "this suspect and other matters".The CPS said that the police had "recently sent us a substantial quantity of papers which we are now examining".